Equivalent & Substitute Parts for MF-R050-AP-99

Part Overview

The MF-R050-AP-99 is a Polymeric PTC Resettable Fuse manufactured by Bourns Inc. in the Multifuse® MF-R series. This component is rated for 60V maximum voltage with a 500 mA hold current and is designed for through-hole radial mounting in disc configuration. The part is currently listed as obsolete, making identification of suitable substitute components necessary for ongoing design support and procurement.

Key Parameters

Parameter	Value
Voltage - Max	60V
Current - Hold (Ih) (Max)	500 mA
Current - Trip (It)	1 A
Resistance - Initial (Ri) (Min)	410 mOhms
Resistance - Post Trip (R1) (Max)	1.17 Ohms
Operating Temperature	-40°C ~ 85°C
Mounting Type	Through Hole
Package / Case	Radial, Disc
Size / Dimension	0.311" Dia x 0.122" T (7.90mm x 3.10mm)
Lead Spacing	0.201" (5.10mm)

Substitute Part Grouping Explanation

Substitution for the MF-R050-AP-99 is determined by electrical and mechanical compatibility across the following critical parameters:

Electrical Parameters:

Voltage rating must equal or exceed 60V maximum
Current hold (Ih) rating must equal 500 mA
Current trip (It) rating must equal 1 A
Resistance characteristics (initial and post-trip) must match specified tolerances

Mechanical Parameters:

Mounting type must be through-hole radial
Package configuration must be radial disc
Physical dimensions and lead spacing must be identical to ensure PCB compatibility

Compliance Parameters:

RoHS3 compliance required
Approval agencies must include cURus and TUV certifications

The substitute parts identified maintain identical electrical performance and physical form factor while differing in voltage rating (72V variants) or packaging configuration (cut tape versus tape & box).

Parameter Comparison

Parameter	MF-R050-AP-99	MF-R050-AP	MF-RX050/72-AP	MF-RX050/72-AP-17
Voltage - Max	60V	60V	72V	72V
Current - Hold (Ih) (Max)	500 mA	500 mA	500 mA	500 mA
Current - Trip (It)	1 A	1 A	1 A	1 A
Current - Max	40 A	40 A	40 A	40 A
Resistance - Initial (Ri) (Min)	410 mOhms	410 mOhms	410 mOhms	410 mOhms
Resistance - Post Trip (R1) (Max)	1.17 Ohms	1.17 Ohms	1.17 Ohms	1.17 Ohms
Operating Temperature	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole
Package / Case	Radial, Disc	Radial, Disc	Radial, Disc	Radial, Disc
Size / Dimension	0.311" Dia x 0.122" T (7.90mm x 3.10mm)	0.311" Dia x 0.122" T (7.90mm x 3.10mm)	0.311" Dia x 0.122" T (7.90mm x 3.10mm)	0.311" Dia x 0.122" T (7.90mm x 3.10mm)
Lead Spacing	0.201" (5.10mm)	0.201" (5.10mm)	0.201" (5.10mm)	0.201" (5.10mm)
Product Status	Obsolete	Active	Active	Active
Packaging Type	-	Cut Tape (CT)	Cut Tape (CT)	Tape & Box (TB)
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Approval Agency	cURus, TUV	cURus, TUV	cURus, TUV	cUL, cURus, TUV, UL

Engineering Selection Recommendations

Primary Substitute: MF-R050-AP

The MF-R050-AP is the direct electrical and mechanical equivalent to the MF-R050-AP-99. Both components maintain identical voltage, current, and resistance specifications with matching physical dimensions and lead spacing. The MF-R050-AP is currently in active production status with higher inventory availability (5601 pcs) compared to the obsolete MF-R050-AP-99. This part is supplied in cut tape packaging and carries full RoHS3 compliance with cURus and TUV certifications.

Secondary Substitutes: MF-RX050/72-AP and MF-RX050/72-AP-17

The MF-RX050/72-AP and MF-RX050/72-AP-17 are voltage-rated variants rated for 72V maximum, compared to the 60V rating of the MF-R050-AP-99. All other electrical parameters remain identical: 500 mA hold current, 1 A trip current, and matching resistance characteristics. Physical form factor and lead spacing are preserved. These parts are suitable for applications where the circuit operates at voltages below 60V, as the higher voltage rating provides additional safety margin. The MF-RX050/72-AP-17 includes expanded approval certifications (cUL, cURus, TUV, UL) and AEC-Q200 automotive qualification, supplied in tape & box packaging.

Frequently Asked Questions (FAQ)

Q: Can MF-R050-AP be used as a direct replacement for MF-R050-AP-99?

A: Yes. The MF-R050-AP is electrically and mechanically identical to the MF-R050-AP-99. Both components share the same voltage rating (60V), current specifications (500 mA hold, 1 A trip), resistance characteristics, physical dimensions, and lead spacing. The primary difference is product status: MF-R050-AP is active production while MF-R050-AP-99 is obsolete.

Q: What is the difference between MF-R050-AP and the MF-RX050/72-AP variants?

A: The MF-RX050/72-AP and MF-RX050/72-AP-17 are rated for 72V maximum voltage, compared to 60V for the MF-R050-AP. All other electrical parameters are identical. The 72V variants are suitable for circuits operating below 60V and provide higher voltage margin. The MF-RX050/72-AP-17 includes additional certifications (cUL, UL) and AEC-Q200 automotive qualification.

Q: Are there packaging differences between the substitute parts?

A: Yes. The MF-R050-AP is supplied in cut tape (CT) packaging. The MF-RX050/72-AP is also supplied in cut tape (CT). The MF-RX050/72-AP-17 is supplied in tape & box (TB) packaging. All three maintain identical physical dimensions and lead spacing for PCB compatibility.

Q: Do all substitute parts meet RoHS3 compliance?

A: Yes. The MF-R050-AP, MF-RX050/72-AP, and MF-RX050/72-AP-17 are all ROHS3 compliant with REACH unaffected status.

Q: Which substitute part has the broadest approval certifications?

A: The MF-RX050/72-AP-17 carries the most comprehensive approval certifications: cUL, cURus, TUV, and UL. It also includes AEC-Q200 automotive qualification. The MF-R050-AP and MF-RX050/72-AP carry cURus and TUV certifications.

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